Technology continues to advance at a rapid pace, oftentimes leaving in its wake a sea of outdated, or legacy, technological devices that need updating, upgrading, or even replacing. A case in point is in televisions. The United States is currently undergoing a transition from the old analog television signal format established by the National Television Systems Committee (NTSC) in the 1940s and 50s to a new digital signal format established by the Advanced Television Systems Committee (ATSC). With this change, many analog NTSC televisions are becoming outdated.
The same is true for other advances in television technology, such as in advances in video compression and data modulation techniques. For example, digital video may be transmitted according to the Moving Pictures Expert Group's (MPEG) MPEG-2 format. As new and improved formats or modulations are developed (e.g., MPEG-4, DVB-C2 (Digital Video Broadcasting—Cable 2)), devices that were configured to process the older formats become outdated and require replacement or upgrading.
Upgrading and replacing devices can be costly and inconvenient, and there is an ever-present need to provide backwards compatibility for legacy devices in as easy a manner as possible.